unfortunately, i lost the two flat-headed mounting screws wich are needed to put my MVR-100 and my heat transfer plate together.What kind of screws where they? I tried to find them at local stores here but without any luck so far.

According to the following diagram it looks like you should be looking at #6-32 flat head screws, unfortunately it doesn't specify the length but it's probably in the 15mm range based on the other measurements.

Being a Canadian Metric and Imperial parts and tools are common due to how close we are to the US. I could definitely see imperial based parts being uncommon stock in other countries. I'm glad you got it resolved.